from math import pi, cos, degrees, radians

def birfday(age, deg_lat, length="s"):
    latitude = radians(deg_lat)      #need to convert to rads
    earth_radius = 6371    #km
    year = 365.24
    earthsun_dist = 146000000    #km
    
    orbit = pi*(earthsun_dist*2)
    lat_rad = (earth_radius*2)*cos(latitude)
    diam = (pi*lat_rad)   #Diameter of earth at latitude (perpenducular to the axis of rotation.
    year_trav = diam*year
    
    #Total aproximate distance moved in one year by a person standing on earth staying roughly in the same place ->
    #distance moved by earth around sun x distance moved by rotation of earth
    one_year_dist = orbit + year_trav
    
    # distance travelled by [age] years:
    end_dist = int(age*one_year_dist)    
    lightyr_comp = end_dist/9460730472580.8
    
    # Messages
    if length == "s":   #short message
        out = [("You have travelled somewhere in the region of %dkm since you were born!" % (end_dist)), ("That's about %f light years" % (lightyr_comp))]
    else:     #verbose explaination
        out = [
                   "Given that the mean radius of the earth is 6,371km:",
                   ("The circumference of the earth at your latitude (%f) = pi*6371*2*(cos(%f))" % (deg_lat, deg_lat)),
                   ("Thus you would travel %dkm per day." % (lat_rad)),
                   ("In one year you would travel 365.24*%dkm ~= %dkm on the face of the planet, this doesn't account for the earth's rotation though."% (lat_rad, int(year_trav))),
                   ("Since the earth is around 146,000,000km from the sun, a single, averaged orbit ~= pi*146000000*2 or 917345054.8km"),
                   ("Multiplying distance travelled on the earth's surface by the distance travelled in an orbit around the sun = %dkm."% (int(one_year_dist))),
                   "Finally, we must account for your age.",
                   ("You're currently %d years old so %d times the distance travelled in one year is the actual distance you've travelled." % (age, age)),
                   ("You've travelled %dkm since you were born!" % (end_dist)),
                   "The next time someone tells you that you're going no-where in life tell them how wrong they are..."
                   ]
    return out


if __name__ == "__main__":
    age = 25
    deg_lat = 54.4
    length = "v"
    out = birfday(age, deg_lat, length)
    for line in out:
        print(line)
        
    out = birfday(age, deg_lat, "s")
    for line in out:
        print(line)
    

if __name__ == "__main__":
    age = 25
    deg_lat = 54.4